Train control system for single track railroads



Sept. 22, 1931.

W. H. REICHARD TRAIN CONTROL SYSTEM FOR SINGLE TRACK'RAILROADS SLOW ACTING- Filed April 10, 1925 Patented Sept. 22, 1931 warren STATES PATENT OFFICE VVADE H. REICI-IARD, OF ROCHESTER, NEW YORK, ASS IGNOR TO GENERAL RAILWAY SIGNAL COMPANY, OF ROCHESTER, NEW YORK TRAIN CONTROL SYSTEM FOR SINGLE TRACK RAILROADS Application filed April 10, 1925. Serial No. 22,127.

will operate to control trafiic in either direction without changes in the circuits of the trackway or the car-carried control apparatus.

It is often found desirable to provide a sys- 5 tem of automatic train control which acts to restrict the progress of the train only if the engineer fails to observe a restrictive signal indication, and to perform a certain act of acknowledgment in response to such restrictive indications, thereby manifesting his vigilance and signifying that he has observed and understood the restrictive signal.

With the above and other considerations in mind, it is proposed in accordance with the present invention to provide a train control system of the continuous inductive type in which the relative locations of the car-carried receiving equipment and the trackway transmitting apparatus is such that proper 39 control will be maintained over the vehicle regardless of its direction of travel. It is further proposed to provide a system in which the engineer is forced to manifest his vigilence by performing an acknowledging act at each restrictive signal encountered in order to prevent an automatic brake application, and in which the trackway means for enforcing this acknowledging act is protected against failure-by means of circuit connections which 4.0 will cause an automatic brake application if said trackway means fails.

Further objects, advantages, and desirable features of the present invention will become apparent as the description thereof pro- In describing the invention in detail, reference will be made to the accompanying drawing, in which a section of trackway equipped for automatic train control of the type embodying this invention has been shown in a diagrammatic and conventional manner, together with thecar-carried apparatus and circuits for use therewith.

Referring more particularly to the trackway equipment, the track rails 1 and 2 are divided into blocks by the insulating joints 3, a portion of the blocks I and J having been shown. It is to be understood that the trackway equipment shown is intended for traffic operation in either direction along the trackway. F or this reason, apparatus for applying train control current to the track rails is located at both ends of each block, the apparatus shown associated with the block I being used when the traffic is east bound, (left to right), and the apparatus associated with the block J being used when the traffic is west bound (right to left). In describing the present invention, it is assumed that the traflic is east bound, and for this reason the trackway apparatus shown associated with the block I only will be described, the corresponding elements and devices associated with the block J being referred to by like reference characters having distinctive exponent-s.

An alternating train control current is applied to the two track rails in series at the exit end of each block with reference to the direction of traffic, from the secondary winding of the transformer 4: through a resistance unit 5 and a circuit which is obvious from the drawing. The primary winding of the transformer 4 is energized from a second transformer 6 through a circuit including the contact finger 7 and front contact of a home relay H, the transformer 6 being energized through the wires 8 and 9 from a third transformer 10 connected to a transmission line 11. The circuit including the primary winding of the transformer 6, the secondary winding of the transformer 10 and the wires 8 and 9 has a portion thereof, indicated at 12, arranged in close proximity to the right hand track rail 1,'this portion 12 being placed and the circuit being connected in such a manner that the magnetic field caused by the current flowing in this wire will be similar in direction and location to a magnetic field resulting from a current flowing in the track rail. This wire 12, which will be hereinafter termed the acknowledging loop, is located a short distance in the rear of the exit end of each block, at a point from which the signal at the entrance to the next block in advance is clearly visible.

The home relays H and H are-the usual home relays used in the well known absolute permissive block type of signal and train control system such as the system shown in the patent to W. W. VVenholz, No. 1,623,023, dated March 29, 1927. no part of the present invention, the control of these relays is not shown, it being understood that this control is so arranged that the presence of a train, a broken rail, or other hazard in a given block will cause the deenergization of the home relay which controls the application of train control current to the rails of the first block in the rear of said given block with reference to the direction of trafiic under which the trackway section is operat- 111 TVayside signals of the semaphore, color light signal, or other suitable type will preferably be used in connection with the train control system of this invention. For the purpose of illustration, two semaphore signals Z and Z have been shown at the point of divisionbetween the blocks 1' and J, it being assumed that the signal Z indicates traflic conditions of'the block J when the traffic is east bound, and that the signal Z indicates traffic conditions in the block I when the traffic is west bound. The signals Z and Z have been illustrated in a conventional manner only, their well known operating means and control circuits being omitted for the sake of simplifying the disclosure.

A railway vehicle has been conventionally shown in the block I by the wheels and axles A1. A receiving coil 13 of the type now common in train control practice is mounted in front of the leading axle of the vehicle, in inductive relation to the'right hand track rail with reference to the assumed east bound direction of traffic, so that voltages will be induced in this coil by control currents flowing in the track rail and in the acknowledging loop 12. The coil 13 is connected to the input circuit of a suitable amplifier, preferably of the audion tube type, which has been conventionally represent-ed at A, this input circuit being preferably tuned to resonance at the frequency of the train control current by means of a condenser T connected in parallel with the receiving coil as shown. The output of the circuit of the amplifier A is connected to a main car relay MB. This relay may be of the alternating current or direct current two-position type, and is provided with a contact finger 14 having back. and

front contacts, conveniently represented by arrows.

. A reset push button and an acknowledging push button Ads are provided in As-this system forms connection with the car-carried apparatus. The reset push button RB is preferably located in a boX or housing which is ascessible only from the ground, in order that the train must be brought to a stop before this push button can be operated. The housing enclosing the reset push button may be provided with a sealing means or a counting device in order that the operation of this push button by the engineer may be recorded. The acknowledging push button Ac/c is preferably located in the cab of the vehicle within easy reach of the engineer, and is provided with two movable contact fingers 15 and 16. The contact finger 15 is arranged to cooperate with a stationary front contact, conveniently represented by the arrow 17, and is arranged to have a time delay, that is, the contact finger 15 will not disengage the front contact 17 until a predetermined time interval after the push button is depressed. This feature may be accomplished in any suitable manner, but for the purpose of illustration, a simple dash-pot 18 serving to resist for a time, the movement of the con tact finger 15, has been shown, the finger 15 being provided with a flexible contact mem ber 19 which remains in contact with the front contact 17 until the dash-pot 18 has moved to its lowest position.

The vehicle brakes may be controlled in any suitable manner and by means of any suitable automatic control apparatus. Since the automatic initiation of a brake applica tion is usually controlled by the opening of a valve, an electro-pneumatic valve EPV has been shown, it being assumed that this valve acts in some suitable manner to initiate a brake application upon the de encrgization of a circuit through its windings. The electro-pneumatie valve EPV is provided with a movable contact member 20 which is ar-' ranged to cooperate with two stationary contacts 21 and 22 and to electrically connect these stationary contacts when the valve is energized. The electro-pneumatic valve EPV is preferably of the slow acting type,

that is, the valve and its contacts will notv be opened until a given interval of time after the de-energization of its winding, the purpose of this slow acting feature being hereinafter described.

0pemton.-Considering first the oper. tion of the system embodying the present in vention under clear trafiic conditions ahead, that is, with no train in the block in which the train under consideration is located or in the first block in advance thereof, an alternating control current is impressed on the track rails ahead of the train from the transmission line 11 through the transformer 10, wires 8 and 9, the transformer 6 to the transformer 4' through the contact finger 7 and front contact of the home relay H which is energized under clear conditions,

through the resistance unit 5 to the tr ck rails l and 2 and the wheels and axles of the vehicle. This current induces avoltage in the receiving coil 13 which voltage is impressed upon the amplifier A, amplified thereby and energizes the main relay MR through circuitswhich are obvious from the drawing. With the main relay MR energized, an energizing circuit for the electropneumatic valve EPV is completed, which circuit may be traced as follows :from the battery terminal B, through contact finger 14 and front contact of the main relay MR, wires 23 and 24, front contact and contact finger 25 of the reset push button RB, wires 26 and 27, contact finger 15 contact member 19 and front contact 17 of the acknowlec ging push button A070, wire28, and the winding of the electro-pneumatic valve EPV to the battery terminal C. WVith the electro-pneumatic valve thus energized, the train under consideration may proceed in the clear territory without automatic restriction.

Considering now therestrictions imposed on a train under unfavorable trafiic conditions, assume that the train under consideration approaches the entrance to a block in which caution trailic conditions exist, that is, the first block to the rear of an occupied block. the trackway, he is informed that the train is about to enter a caution block by the aspect of the wayside signal Z at the block entrance. As the train approaches the exit end of the last clear block, the engineer should depress the acknowledging push button A070, and hold this push but-ton down, releasing it just as the train enters the caution block. When the acknowledging push button A070 is depressed, a pick-up circuit for the stick relay S is completed, this circuit being traceable as follows :from the battery terminal B, through contact finger 1 1 andfront contact of the main relay MR, wires 23 and 24, front contact and contact finger 25 of the reset push button RB, wire 26, contact finger 16 andback contact of the acknowledging push button A070, wires 30 and 31 and the winding of the stick relay S to the battery terminal C. The dash-pot 18 and flexible contact member 19 associated with the contact finger 1501? the acknowledging push button Ac7c maintain the elec tro-pneumatic valve EPV energized for the period during which the acknowledging push button is depressed. No control current flows in the track rails of the caution block due to the fact that the home relay H at the exit end of this block is dc-cnergized, and for this reason the receiving coil 13 fails to have a voltage induced therein and the main relay MB is de-energized as the train enters the caution block. A stick circuit for the stick relay Sis completed when the main relay MR is (lo-energized, this circuit being If the engineer is alert and watching- S, wires 35 and 31 and the winding of the stick relay S to the terminal C. The stick relay S is sufiiciently slow acting to prevent it opening its contact 34- in the interim that contact 1 1 of the main relay MR moves from its normal to its abnormal position. Vith Z the stick relay S energized, an energizing circuit for the electro-pneumatic valve EPV is completed, which circuit may be traced as follows :from the battery to 'minal B, contact finger 36 and front contact of the stick relay S, wire 37, contact members 20, 21 and 22 of the elcctro-pneumatic valve EPV, wires 38 and 24, front contact and contact finger 25 of the reset push button RB, wires 26 and 27, contact finger 15 contact member 19 and front contact 1'? of the acknowledging push button Acts, wire 28 and the winding of the electro-pneumatic valve EPV to the battery terminal C. lVith the electro-pneumatic valve EPV thus energized, the train under consideration may proceed in the caution block without restriction.

If, as the train under consideration approaches the exit end of the caution block, -he next block in advance is occupied and the signal at danger, the engineer should again depress the acknowledging push button A070, as the train approaches the signal and the receiving coil 13 passes through the magnetic field set up by acknowledging loop 12. ,.u

A voltage is induced in the receiving coil 13 as it passes over the acknowledging loop, and this voltage is impressed upon the amplifier A, is amplified and causes the main relay M3 to be momentarily energized, attracting its contact finger 14 and thus breaking the stick circuit to the stick relay S, which circuit has been tracer above. The stick relay S is, however, maintained energized through the front contact of the main relay MR and the back contact of finger 16 of the acknowledging push button Ac7s and a circuit which has been traced. The acknowledging push button should be released by the engineer as the receiving coil passes out of? the field of the acknowledging loop 12, and the stick circuit for the stick relay S is completed through the contact finger 14 and back contact of the main relay MR as described above. The electro-pneumatic valve EPV is again maintained energized through the circuit including the contact finger 36 of the stick relay S, which circuit has been traced, and with the electro-pneumatic valve so energized, the train may proceed without restriction in the danger block.

If the engineer fails to actuate the acknowledging push button Acl: upon the entrance of the train under consideration into a caution block from a clear block, the circuit to the electro-pneuinatic valve is broken by the retraction of the contact finger 14 of the main relay MR, and the stick relay S is not picked up to maintain the electro-pneumatic valve EPV energized. After a predetermined time interval, the electro-pneumatic valve actsto cause an automatic brake application which continues until the train has been brought to a stop. In order that the train may again proceed, the reset push button RB must be depressed simultaneously with the depression of the acknowledging push button A070, whereupon the stick relay S is energized through the following pickup circuit :from the battery terminal B through contact finger 14 and back contact of the main relay MR, wires 32 and 39, back contact finger of the reset push button RB, wire 26, contact finger 16 and'back contact of the acknowledging push button A072, wires and S1 and the winding of the stick relay S to the battery terminal C. Once picked up, the stick relay S is stuck up through a circuit including the contact finger 14 and back contact of the main relay, MR, which circuit has been traced.

Considering now the failure of the engineer to acknowledge a danger signal while approaching the exit end of a caution block, the main relay MB is momentarily energized by-the acknowledging loop 12, causing its contact finger 14 to be attracted and thus breaking the stick circuit to the stick relay S and permitting this stick relay to retract its contact fingers,'no pick-up circuit to the stick relay being completed when the acknowledging push button A070 is not depressed. The receiving coil 14 quickly passes out of the influence of the acknowledging loop 12, and the main relay is again de-energized. With the stick relay S die-energized and the main relay MR also de-energized, the stick relay cannot be re-energized by depressing the acknowledging push button A070, and for this reason, the circuit to. the electro-pneumatic valve EPV cannot be completed through the finger 36 of the stick relay and an automatic brake application results, bringing the train to a stop. The stick relay S can now bepicked up and the electro-pneuinatic valve energized by a simultaneous depression of the reset push button RB and acknowledging push button A07: as described above Depression of the reset push button contact 25 close-s the folowing pick-up circuit for the device EPV beginning at B, contact 14 retracted, wires 32 andiiil. contact 25, wires 26 and 2'7, contact 15, wire 28, to the winding of the device EPV Depression of the acknowledging push button simultaneous with depression of contact 25 closes the following pickup circuit for the relay S :-beginning at B, contact 14 retracted, wires 32 and 39, contact 25 depressed, wire'26, contact 16 depressed, wires 30 and 31' to the winding of the relay S. Immediate- 1y upon picking up of the relay S the device EPV is again stuck up through its stick circuit heretofore traced.

It is seen from the foregoing discussion that the train control system of the present invention permits-the engineer to avoid a restrictive brake application if he is alert, recognizes the trackway conditions from the aspect of the wayside signals and properly acknowledges each restrictive signal indication. It should be particularly noted that in order to avoid an automatic brake application, the engineer must acknowledge successive stop or danger signals, as the acknowledging loop 12 is permanently maintained energized and always acts to cause the energization of the main relay MR, thus breaking the stick circuit so the stick relay S, which stick relay must then be maintained energized through the acknowledging push button A070 in order to avoid automatic brake application.

Although acknowledgment is enforced under danger and caution 'trafiic conditions, the failure of the engineer to acknowledge a restrictive signal does not result in a brake application if the traffic conditions ahead immediately become clear. For instance, if the engineer, on approaching a caution signal fails to-acknowledge, but the caution block becomes a clear block as the train under consid eration enters, the main relay 134R and consequently theelectro-pneumatic*valve, EPV remain energized and no automatic brake application results.

If the engineer attempts to maintain the stick relay S energized by depressing the acknowledging push button A076 and main taining this push button so depressed, the contact finger 15 will drop after a predetermined interval and the resilient contact member 19 will disengage its'front contact 17, opening'the energizing circuit to the electro-pneumatic valve and causing an automatic brake application. In this Way, the acknowledging push button A070 is protected against misuse.

In the application of a train control system of the continuous inductive type to existing railway systems, points are encountered such as crossings, switch frogs, and the like, where it is difiicult to maintain the control current in the track rails. In order that such dead sections, (as they are sometimes called), may not cause a brake application, the electropneumatic valve EPV is made slow acting as pointed out above, so that a brake application will not be initiated until the electropneumatic valve has remained de-energized for a predetermined period of time. The time required for the operation of the electropneumatic valve is so arranged that the longest of such dead sections ordinarily encountered in practice may be-crossed without a brake application if the train is traveling above a given speed.

The acknowledging loop 12 is energized di rectly from the transmission line 11 as shown, and it is essential that this loop bemaintained energized at all times in order to enforce acknowledgment at successive danger signals as described above. In order to check the energization of this loop 12,-the train control current is applied to the track rails through a circuit including this loop, and if current is not flowing in the loop by reason of a broken wire or for any other reason, the train control current is cut ofl from the track rails and a restrictive control is thereby set up, bringing the train to a stop when it enters the block in which such de-energized loop is located. This results .in an automaticbrake application under clear traftic conditions, and indicates to the engineer that the trackway appa- -atus is out of order, thus quickly locating a failure in the trackway equipment.

It should be clearly understood that the apparatus and circuits described in connection with the present invention have been used to illustrate its nature only and should not be considered as limiting its scope.- It should be further understood that the present train control system might be modified and combined with other features and systems without departing from the spirit of the present in vention as defined bythe appended-claims.

lVhat it is desired to be secured by Letters Patent is 1. In an automatic train control system, a car-carried relay energized by influences inductively received from the trackway, means for applying the vehicle brakes when said relay is die-energized, means for suppressing said brake application if a manually actuable device is actuated before said relay is de-energized, trackway means for continuously supplying said influences to energize said relay under favorable traflicconditions and for cutting said influences to de-energize said relay under unfavorable trafiic conditions, and further trackway means for momentarily supplying said influences at spaced points under all traflic conditions for momentarily energizing said relay, manually actuab-le resetting means for permitting rel ase of the vehicle brakes, and means for preventing said resetting means being left in its active condition permanently.

2. In an automatic train control system of the type in which control influences corre-- sponding to traflic conditions are continu-' ously transmitted inductively from the trackway to a moving vel11cle,1-n combination wlth car-carried apparatus for applying the vehicle brakes upon the cessation of the reception of control influences from the trackway, and a car-carried manually actuable device effective to prevent said brake application if and only if actuated before and released after the cessation of said influences, trackwayapparatus comprising means for transmitting control influences continuously under favorable trafiic. conditions and means for trans mitting control influences only at spaced points along the trackway under unfavorable traflic conditions, whereby said manually actuable device mustbe actuated at predetermined intervals of travel under unfavorable trafiic conditions to avoid a brake application.

3. In an automatic train control system, means for transmitting control influences from the'trackway to a moving vehicle continuously under favorable traflic conditions only, means at spaced points along the trackway for constantly transmitting control influences for a limited distance of vehicle travel, car-carried apparatus including means for causing a brake application upon the cessation of the transmission of control influences, and means for avoiding said brake application if and only if a manually actuable means is initiated before and is released after the cessation of the transmission of said influences.

4:. In an automatic train control system of the type in which control influences corresponding to traflic conditions are continuously transmitted inductively from the trackway to a moving vehicle, in combination with carcarried apparatus for applying the vehicle brakes upon the cessation of the reception of control influences from the trackway and a car-carried manually actuabl'e device for preventing said brake application if actuated be fore and released after the cessation of said influences, trackway apparatus for transmitting said control influences comprising track rails divided into blocks, means for applying control influences to the track rails of said blocks under favorable traflic conditions and for cutting'ofl said control influences-under unfavorable traiflc conditions ahead, acknowL edging loops for transmitting control influences for a limited distance of vehicle travel at points near one end of each of said blocks, said acknowledging loops being active to transmit influences under all traflic conditions, and circuits for supplying said influences to the track rails of each of said blocks from circuits including said acknowledging loops, whereby the cessation of said influence insaid acknowledging loops will cause the cessation of said influences in the track rails of the corresponding block,

5. In an automatic train control system, in combination with car-carried apparatus for receiving influences corresponding to alternating control currents flowing in the track rails and for causing an automatic brake application upon'thecessation of said control currents, manually actuable means'for suppressing said automaticrbrake application if actuated before and released immediately after said currents cease to flow, trackway apparatus for carrying said currents comprising the usualtrack rails divided into blocks, ac-

knowledging loops arranged in close proximity to one track rail near the exit ends of each of said blocks, means for continuously supplying alternating current to said loops, and means for supplying alternating current from said loops to said track rails of the corresponding block under favorable trafiic conditions only, whereby when a train is traveling under unfavorable traffic conditions said manually actuable means must be actuated to avoid an automatic brake application when said acknowledging loops are passed. 6. In an automatic train control system of the type in which control influences corresponding to traffic conditions are continuously transmitted from the trackway to a moving vehicle, means for applying the vehicle brakes in response to influences corresponding to unfavorable traffic conditions ahead, manually actuable means effective to suppress said brake application if and only if actuated before and released after said unfavorable influences are received, and means located at spaced points along the trackway for causing the vehicle brakes to be reapplied successively under unfavorable traffic conditions unless said manually actuable means is actuated and released at said spaced points.

7. In an automatic train control system of the continuous inductive type, in combination with a section of trackway divided into the usual blocks and equipped with signals for train travel in either direction, means for continuously transmitting influences corresponding to traffic conditions from both of 'thewtrack rails, constantly active influence transmitting means located adjacent one of the track rails at one end of each block and adjacent the opposite track rail at the opposite end of each block, and receiving means located on a vehicle and adjacent one of the t 'ack rails, whereby said vehicle may receive influences corresponding to traffic conditions when traveling in either direction, and may receive further influences from said constantly active transmitting means located adjacent one of the track rails when traveling in one direction, and from said constantly active transmitting means located adjacent the other of the track rails when traveling in the other direction.

8. In an automatic train control system, in combination with car-carried apparatus comprising a main relay, an automatic brake control device maintained energized by the energization of said main relay and adapted to apply the vehicle brakes when de-energized, and manually actuable means for maintaining said brake control device energized if actuated before the de-energization of said main relay, influence transmitting apparatus comprising a car-carried receiver controlling said main relay and located on one side of the vehicle, trackway means for transmitting influences to said receiver under favorable traffic conditions from either of the track rails, and spaced means located adjacent one of the track rails for periodically transmitting influences to said receiver when the vehicle is traveling in one direction and further spaced means located adjacent the opposite track rail for periodically transmitting influences to said receiver when the vehicle is traveling in the opposite direction.

9. In an automatic train control system of the type in which control influences corresponding to traffic conditions are continuously transmitted inductively from the trackway to a moving vehicle, car-carried apparatus including means for initiating a brake application upon a change from favorable to unfavorable traffic conditions and manually actuabl means for suppressing the initiation of said brake application effective if and only if actuated before and released after said change from favorable to unfavorable traffic conditions, and means for initiating brake applications at successive spaced points along the trackway under continued unfavorable traffic conditions, said manually actuable means operating to suppress the initiation of said brake applications under continued unfavorable traffic conditions if maintained actuated while said spaced points are passed.

10. In an automatic train control system of the continuous inductive type for railroads of the single track type, the combination with a track divided into blocks by insulating joints, a car carried relay energized by influences inductively received from the trackway, means for applying the brakes of the vehicle when said relay is de-energized, means for suppressing said application of the brakes if a manually actuable device is actuated before said relay is de-energized, trackway means for continually supplying said influences to energize said relay under favorable traffic conditions and for discontinuing the supply of said influences to deenergize said relay under unfavorable traffic conditions ahead, and other trackway means near the eXit end of each block regardless of the direction a vehicle is traveling in such block for momentarily supplying said i11- fluences while said vehicle passes such other trackway means for momentarily energizing said relay regardless of traffic conditions ahead, whereby said manually actuable device must be actuated upon passage of said vehicle by said other trackway means under unfavorable traffic conditions to avoid a brake application.

11. Car-carried apparatus for automatic train control systems comprising; an electrically operated brake control device having a contact closed only if said device is energized, which device will effect a brake application if de-energized; a control relay energized in response to current flowing in the track rail ahead of the vehicle; a circuit for said brake control device including a contact closed if said control relay is energized; a stick relay;manually actuable means for picking up said stick relay; a stick circuit for said stick relay includingits winding its front contact and a contact closed if said control relay is tie-energized; and another circuit for energizing'said brake control device including the contactof said brake control device anda contact closed when said stick relay is energized.

12. Car-carried apparatus for automatic train control systems comprising; an electrically operated brake control device having a contact closed only if said device is energized, which device will effect a brake application if (lo-energized; a control relay energized in response to current flowing in the track rail ahead of the vehicle; acircuit for said brake control device including contacts closed if said control relay is energized; a stick relay; manually actuable means for picking up said stick relay; a stick circuit for said stick relay including its winding its front contact and a contact closed if said control relay is tie-energized; another circuit for energizing said brake control device including the contact of said brake control device and a contact closed when said stick relay is energized, and means for preventing said manually actuable means being left in its active condition permanently.

13. In an automatic train control system of the continuous inductive type for ra lway systems of the single track type facilitating the movement of trains inboth directions; the combination with a track divided into blocks by insulatingjoints: means for supplying train control current from the exit end of each block when trailic may move in a particular direction, which current flows toward the train in one rail. through axles of the train and away from the train in the other rail when trafiic conditions in advance are favorable; a car-carried relay energized in response to such trackway current; a brake control device maintained inactive so long as said relay is energized; means for maintaining said brake control device inactive while said relay is de-energized requiring the operation of a suitable manually actuable device each time and before said relay assumes its de-energized condition; and other trackway means located at the junctions of blocks for causing said relay to assume its energized condition while a train passes such junction effective regardless of traliic'con'dt tions ahead; whereby said manually actuable device must be operated upon the em trance of the train into each block under ad verse traffic conditions to avoid an automatic,

the continuous inductive type for railway systems of the single track type facilitating the movement of trains in both directions; the combination of a track divided into blocks by insulating joints; means for supplying train control current from the exit end of each block when trafiic may move in a particular direction; which current flows toward the train in one rail, through axles of the train and away from the train in the other rail when trahlc conditions in advance are favorable; a car-carried relay energized in response to such trackway current; a brake control device maintained inactive so long as said relay is energized; means for maintaining said brake control device inactive while said relay is de-energized requiring the oper ation of a suitable manually actuable device each time and before said relay assumes its de-energized condition; and other trackway means located at the junctions of blocks for causing said relay to assume its energized condition while a train passes such junction effective regardless of traffic conditions ahead and means for checking the operative condition of said other trackway means; whereby said manually actuable device must be operated upon the entrance of the train into each block under adverse traffic conditions ahead to avoid an automatic brake application.

15. In an automatic train control system, a car-carried relay ener ized by influences inductively received from the trackway, means for applying the vehicle brakes when said relay is de-energized, means for suppressing said brake application if a manually actuable device is actuated before said relay is de-energized trackway means for continuously supplying said influences to energize said relay under favorable trafiic conditions and for cutting off said influences to de-encrgize said relay under unfavorable traffic conditions, and other trackway means for momentarily supplying said influences at spaced points under all traflic conditions for mome11- tarily energizing said relay and means for checking the operative condition of said other trackway means whereby said manually a etuable device must be actuated at such spaced points under unfavorable tratfic conditions to avoid a brake application.

16. In an automatic train control system of the type in which control influences which correspond to traflic conditions are continuously transmitted inductively from the trackway to a moving vehicle, in combination with car-carried apparatus for applying the vehicle brakes upon the cessation of the reception of control influences from the trackway, and a car-carried manually actuable device effective to prevent said brake application if and only if actuated before and released after the cessation of said influence. trackway apparatus comprising means for transmitting control influences continuously under favorable traffic conditions, other trackway means from the trackway to a moving vehicle continuously but only under favorable traflic condltions, means at spaced points along the trackway for continuously transmitting such influences for a limited distance of vehicle travel, means for checking the operative condition of said last mentioned means, carcarried apparatus including means for causing a brake application upon the cessation of the transmission of control influences, and means avoiding said bra-lie application if a manually actuable means is initiated before the cessation of the transmission of said influences.

18. In an automatic train control system of the type in which control influences corresponding to traflic conditions are continuously transmitted from trackway to a moving vehicle, means for applying the vehicle brakes in response to influences corresponding to unfavorable traflic conditions ahead, manually actuable means effective to suppress said brake application if actuated before said unfavorable influences are received means located at spaced points along the traclrway for causing the vehicle brakes to be reapplied successively under unfavorable trailic conditions unless said manually actuable means is actuated at said spaced points, and means for checking the operative condition of said means located at spaced points along the trackway.

19. In an automatic train control system of the continuous inductive type, in combination with a section of traclzway divided into the usual blocks and equipped with signals for train travel in either direct-ion, means fo continuously. transmitting influences of the tract: rails, constantly active influence transmitting means located adjacent one of the track rails at one end of each block and adjacent the opposite track rail at the opposite end of each block, receiving means located on a vehicle and adjacent one of ther corresponding to traffic conditions from both ting means located adjacent the other of the track rails when traveling in the other dircction.

20. In an automatic train control system of the type in which control influences corresponding to trafiic conditions are continu ously transmitted inductively from the trackway to a moving vehicle, car-carried apparatus including means for initiating a brake application upon a change from favorable to unfavorable trafiic conditions and manually actuable means for suppressing-the initiation of said brake application if actuated before and released after said change from favorable to unfavorable trafiic conditions, and means for initiating brake appli cations at successive spaced points along the traclrway under continued unfavorable traffic conditions, and means for checking the operative condition of. said last mentioned means.

21. Trackway apparatus for automatic train control systems comprising, a stretch of railway track adapted to have alternating current flowing therein for transmitting control influences to a moving vehicle inductively, an auxiliary conductor for transmitting control influences to a moving vehicle inductively, a transformer for supplying alternating current to the track rails of said train control systems comprisin a stretch of railway track adapted to have zilternating current flowing therein for transmitting control influences to a moving vehicle inductively, an aux1l1ary conductor for transmitting control influences to a moving vehicle inductively, translating means for supplying alternating current to the track rails of said stretch of track, a source of alternating current, a circuit for connecting said auxiliary conductor, said translating means and said source of alternating current in series to cause alternating current flow in said auxiliary conductor and said track rails, and means for discontinuing the flow of alternating current in said track rails under unfavorable traflic conditions without discontinuing the flow of alternating current in said auxiliary conductor, whereby failure of flow of alternating current in said auxiliary conductor is indicated by'failuiie of flow of alternating current in said track rails under favorable traffic conditions.

, 23. An automatic train control system of the continuous inductive type comprising, a stretch of railway track, an auxiliary conductor located adjacent said stretch of track, a source of alternating current for causing the flow of alternating current in said auxiliary conductor, means connected in series with said auxiliary conductor and said alternating current source for at times causing the flow of current in the track rails of said stretch of track, and means responsive to trafiic conditions ahead for discontinuing the flow of alternating current in the track rails of said stretch under unfavorable traflic conditions without discontinuing the flow of current to said auxiliary conductor, whereby the failure of the continuity of said auxiliary conductor is checked by the failure of flow of alternating current in said track rails under traflic conditions when where should be alternating current flowing in such track rails.

24. Trackway apparatus for automatic train control systems of the continuous inductive type comprising, a railway track, an auxiliary conductor, a source of alternating current continuously effective to cause a flow of alternating current in said auxiliary conductor, and means governed in accordance with traflic conditions in advance effective to cause the flow of an alternating current in the rails of said railway track only when traffic conditions in advance are favorable including said source of alternating current and effective only if current is then flowing in said auxiliary conductor, whereby the failure of the continuity of the circuit including said auxiliary conductor causes failure of alternating current flow in the rails of the trackway even though trafiic conditions are favorable.

25. Trackway apparatus for automatic train control systems, of the continuous inductive type comprising, a railway track, an auxiliary conductor, a source of alternating current, a traffic controlled device controlled in accordance with traflic conditions, and means governed by said device for causing current from said source to flow in said aux iliary conductor only or for causing current to flow in the rails of said railway track and in said auxiliary conductor depending on the condition of said trafi lc controlled device, said trackway apparatus being connected in a manner such that alternating current cannot flow in said rails unless there is also alternating current flowing in said auxiliary conductor.

26. In combination with a stretch of railway track and a transformer for at times supplying train controlling current to said stretch, an auxiliary conductor located in the trackway and connected in series with the primary of said transformer, and traincarried governing means responsive to the train controlling current in said stretch and also responsive to the transformer magnetizing current flowing in said conductor.

27. In combination, a stretch of railway track, a source of alternating current, an auxiliary conductor located in the trackway, a transformer having its primary connected in series with said auxiliary conductor and with said source, means for at times supplying train controlling current from the secondary of said transformer to the rails of the stretch, and train carried governing means responsive to alternating current flowing in the track rails and also to the magnetizing current for said transformer flowing in said conductor.

28. In combination with a stretch of railway track and train carried governing means responsive to alternating current flowing in the trackway, an auxiliary conductor located in the trackway, a source of alternating current, a first transformer having its primary connected in series with said source andsaid auxiliary conductor, a relay responsive to traflic conditions in advance of said stretch, a second transformer, a circuit for the primary of said second transformer including the secondary of said first transformer and a contact of said relay, and means for supplyin g alternating current from the secondary of said second transformer to the rails of said stretch.

WADE H. REICHARD. 

